Secrets of our Past
by BrightWings111
Summary: When Aizen, Gin, and Tosen betrayed Soul Society, Gin's sister, Rin, is sent on a mission to spy on them in Hueco Mundo. When she gets caught, she refuses to help them in any way. That is, until Gin reveals a secret about their past that changes everything. ToshrioxOC slight AizenxOC rated for language, violence, and lemons
1. Chapter 1

**A/N: I think of this new story as somewhat of a replacement for my story-on-hiatus Fading Star. I hope you like this one!**

"Good luck," Yamamoto says. All of the captains bow their heads in respect. I never thought I'd be this important; _especially_ once Aizen, Gin, and Tosen betrayed us. I thought I'd be killed.

I have an hour to prepare. To prepare for a spying mission in Hueco Mundo.

I make my way back to Squad 10 to get ready. You know, do something with my KNEE-LENGTH black hair and the bangs that completely cover my left eye and most of my right. I need to see to spy, right? But I keep my eyes covered for a reason. They're ORANGE. And I'm talking STRAWBERRY'S HAIR orange. And to change out of my uniform and into my spy clothes. Yes, I have those. They have secret pockets and are much easier to move around in.

I quietly enter my room and turn on my lamp. I strip down to my bra and underwear and grab my spy clothes. I slip on the legging-like leather pants when I hear a knock at the door.

"Who is it?" I call.

"It's me," a familiar voice says.

Oh.

It's him.

"Come in," I say. Yes, I did just tell him to come in while I'm wearing leather pants and a bra.

"How's preparing going?" Toshiro asks, sitting down on my bed and studying me with an amused expression.

"Just fine," I say, pulling a black cami over my head and yanking my hair out of the back.

I walk over to my nightstand, open the bottom drawer, and pull out a fake bottom. It's empty.

"...what the hell?" I mutter.

"Looking for this?" Toshiro asks. I turn and see him holding up my gun holster.

"Hey!"

"Come and get it," he smirks.

I growl and tackle him, pinning him to the bed and straddling his hips. I kiss him fiercely to distract him while I carefully remove the holster from his hand.

When I pull away, he smirks and flips me onto my back, now straddling my hips. He kisses me roughly, but sweetly, his hands roaming my body. When he reaches the top of my pants, I grab his wrist and shake my head slowly.

"We don't have time," I whisper softly.

He looks disappointed, but I can tell he knows I'm right. He gets off and I sit up, softly kissing his cheek.

"When I get back," I murmur in his ear. "I promise."

I stand up and put the holster on my belt.

"Nervous?" he asks.

"Yeah," I respond, pulling my hair back into a high ponytail and clipping my bangs to the side of my head. "This is probably going to be my toughest mission yet."

I grab my zanpakutou and release shikai, putting it in the gun holster.

"How do you do that?" he asks.

"Do what?" I reply, putting on my combat boots and leather jacket.

"Keep your shikai ongoing," he says.

"Practice." I slip knives up my sleeves and in my boots. "You know that this mission involves _him_, right?"

"Which _him_ are we talking about?" he asks.

"...I guess both," I reply. "You know what that means, right? What could happen?"

He nods solemnly. "Yeah."

"Just remember I'm yours and no one else's."

"Is it time?" he asks. I look at him sadly.

"It is."

"Just come back, okay?" he says as I move to the door. I stop in the doorframe and look back at him over my shoulder.

"Remember my promise."


	2. Chapter 2

**A/N: So you may have noticed the rating change and the slight AizenxOC added. Well. Here's your reason why.**

I hesitantly knock on the door of the small shop. The door is opened by a man with blonde hair, wearing a green coat and a striped hat.

When he sees me, his eyes flicker with worry and he tenses slightly. As I would expect from someone when they see a girl dressed in all black and armed.

"Relax," I sigh. "I came for help."

"Come on in, Rin," he says tentatively. I follow him inside, my steps making no sound on the floor.

"So, what's it this time?" he asks, sitting at a small table.

"I need to get into Hueco Mundo without drawing Ai-Aizen's attention," I say. He and I both flinch when I mention Aizen.

I think a couple of explanations are in order.

I began taking spy missions around the time Kisuke became a Captain. One of my first missions was from Shinji. I was supposed to gather information on Aizen and monitor his every step. That was all well and good until he saw me.

I had to think up a very quick explanation as to why I was following him. Shinji had told me of his suspicions, and I couldn't help but agree with him.

One thing led to another, and pretty soon we were… involved, with each other. I have no clue what he thought of it, but it was just my job to me. I never once felt hatred for that man, but he did leave an impression.

"I can't believe they're putting you on another mission with him," Kisuke mutters.

"A mission's a mission," I shrug. "About the Garganta…"

"Five minutes," he interrupts. "You'll be in Las Noches in five minutes."

"Thank you, Kisuke," I say.

"Anytime," he replies, opening a hatch in the floor that leads to his underground desert. "After you."

I jump down without using the ladder and land confidently on my feet. He scurries down the ladder and begins opening the Garganta.

I grab my gun out of boredom and fire at various rocks, hitting each of them dead center.

"Mind not destroying my basement?" Kisuke asks.

"Sorry," I reply. "Got bored."

"Bored, huh?" he chuckles. "The Garganta's ready when you are."

"Thanks again, Kisuke," I say, walking up to the large black tear in the sky. "I'll be back soon... I hope." I walk through without looking back.

Kisuke's Garganta leaves me in Las Noches. In the throne room no less. Damn lucky Aizen's not in here right now. I push myself into the corner, hoping to blend in, but it's just not working. DAMN WHITE WALLS!

I sigh. I know what I need to do for this, but I don't want to. I like this shikai! And I did say _this_, meaning I have another one. Yes and no.

My zanpakutou has a light and a dark side, like white and black. Akuma no Pistoru, Demon's Pistol, is the dark side. In this form, his manifestation is a tall man with long dark hair and hollow pits for eyes. He looks pretty much like a demon man. Hence his name.

His light side, however, is the opposite. Tenshi no Tebukuro, Angel's Gloves, has long golden hair and golden eyes. And wings. He's pretty much an angel warrior. The actual weapon is a pair of white gauntlets, made out of some kind of white super steel, that have a retractable blade on the back of the hand.

I pull a small device out of my pocket, leave it in the corner, and jump out of a window. Yes, jump out of a window. I land silently on my feet and stand right up against the wall so no one looking out of a window can see me.

"So glad I was prepared for this..." I mutter, taking off my jacket and cami and turning them inside out before slipping them back on. Now they're white. I do the same with my leggings and reseal my zanpakutou.

"Sorry bud," I whisper. "I've gotta change your form. Slice, Tenshi no Tebukuro."

_Come on,_ he huffs. _Did you really have to?_

_Yes,_ I reply, pulling white slip-on covers over my boots. _I need to go all-out white for this job_.

_What about your hair?_

_I've already got that under control_. I let my hair down and take a pure white ribbon out of my pocket. I tie my hair back with it and pour a small vial of water on it, causing the white dye from the ribbon to run and dye my hair a light gray.

I activate a small button in my watch, distorting the space around me and transporting me to the device I left in the corner. I grab the device and slip it back into my pocket, pressing myself against the wall so I can focus on what's going on in the doorway.

There are four arrancar there. Three of them seem to be ganging up on the other. The one being ganged up on looks like he doesn't care.

All of the sudden, one of the three slashes at the fourth, and the other two do as well. Well now, that guy looks pretty dead.

"Let's go," one of the remaining arrancar says, and the other two follow him away.

That was... interesting.

Aizen walks in and waves his hand over the dead arrancar's body. The body transforms into a sword in Aizen's hand. So it was Kyouka Suigetsu.

"Aizen-taicho," Gin says, walking in. "Are ya sure i' was okay ta let them believe tha' they killed Ulquiorra?"

I miss Aizen's answer because I'm too busy restraining myself. Self control... self control... self control... FUCK SELF CONTROL!

I pull the knife out of my sleeve and expertly chuck it at my brother. It implants itself in his neck.

But he doesn't fall. He turns and looks at me, his grin widening. Then he starts disappearing. Damn Kyouka Suigetsu... wait, then where's...? FUCK!

Strong hands grab my wrists and twist them behind my back. Geez, could they get any tighter? I'm surprised Tenshi no Tebukuro hasn't cracked under the pressure!

Both of my wrists are transferred to one hand, the other hand cold on the back of my neck. I'm pushed into the center of the room, and forced to my knees.


	3. Chapter 3

**A/N: Okay, this is a dark-themed lemony chapter. This chapter is brought to you by Devil'sEyeAlchemist13. I don't write this. If you don't want to read the lemon then read up until + and then skip to the next +. Enjoy!**

"What do we have here," Aizen says threateningly behind me. "Rin." My mind instantly shifts to defensive mode, plastering a fake look of fear on my face, I look at him over my shoulder and catch his eye.

"Aizen?" I ask. Act scared… act scared… act scared… Ah, screw it, he can see right through me.

"Don't pretend to be scared," he says, leaning close to me. I can feel his breath on the back of my neck. "I know you're not."

"Worth a shot," I shot. "Now why don't you let me get up?"

"Why would I want to?" he counters.

"So I could be out of your way…?" I try, adding a little innocence in my voice. Aizen probably doesn't have a soft spot like that, but it's better to be safe than sorry.

"Who said I wanted you to leave just yet?" His voice slightly darkens as he lifts his hand off the back of my neck. He starts rubbing a piece of my hair between his fingers, the white dye rubbing off on his fingers. "Last time I checked, your hair was considerably darker."

"It's called hair dye. I tried NOT to be found here."

"And that's because of your little promise, right?" I don't reply. All I can think about is how the hell he would know about my promise to Toshiro. Then again, this _is_ Aizen we're talking about; I wouldn't put anything past him. "I'll be sure to tell your little friend that you're mine," he smirks. "Right before I kill him."

"He'll never believe you," I snarl. "He knows about my past. He knows about you. He knows what might happen here. And he knows…" Aizen's eyes narrow. I think he already knows what I'm going to say. "He knows that I'm his and only his no matter what!"

_CRACK!_

A searing pain explodes in my face where his hand connected with my cheek.

"We'll see about that…" he says.

Sliding my jacket down my arms, he starts kissing and licking my neck. I shiver at the feel of him on me. I try to scream for my brother, but before I can, Aizen invades my mouth, advancing on me like he's trying to devour me. I try again to scream, and this time something comes out. Although incoherent, it catches his attention. He smirks before letting go of my wrists. As soon as I try to escape to a door, Aizen pushes me to a part of a wall. Blocked on three sides by another wall, Aizen, and his right limbs against the only other way for me to escape.

Damn bastard.

Before I can really react, he pulls my cami over my head and rips my bra off, leaving my upper body exposed. I never realized how cold Las Noches actually was until now.

He grabs my shoulder and holds me directly to the wall. I wince at the amount of force he uses. He lowers himself to my chest and starts sucking on my breasts, twirling each nipple with his tongue. Then he decides he wants to get a little more than just a hand on me. He uses his other hand to try and cup my face.

I don't think so!

I bite his hand. Hard. And I can tell it hurt because he bit down hard back on my nipple. I shriek in pain as hi raises himself to gaze at his injured hand. Warm blood ebbs from the clear teeth marks on it.

"Now Rin, is that any way to thank me?" he teases. But before I can even get a second to tell him how I REALLY think he should be thanked, Aizen clamps down on my shoulder about an inch away from my neck, probably twice as hard as I bit his hand. All of my thoughts are replaced with agony and anger as he rips my leggings off of me. Tears start to slide down my face as blood drips from my shoulder. He licks the red liquid off me as he fiercely resumes groping me. Then I see an opening. Literally. Taking this once – in – a – sexual – harassment – chance, I kick him squarely in the 'pride' zone, throwing him off and allowing me to slide under him.

And I can't believe I just realized he's hard! Sick bastard!

But the moment, and my hopes, die as Aizen regains himself and throws me back on the floor.

"This is where the pleasure begins," he whispers as he straddles my hips. I shut my eyes and admit defeat.

Suddenly Aizen's weight gets lifted off of me. I stare in shock as he flies into a wall.

"Aizen-taicho," I hear my brother's voice say warningly. "Tha's my li'l sister ya be runnin' yer han's all over."

"I wouldn't get to close to her if I were you, Gin," Aizen chuckles, picking himself out of the wall. "My illusion of you that I used to draw her out got a knife to the neck."

I look over my shoulder at Gin. His eyes are open and glaring at Aizen, only anger burning in them. For once he's not smiling. "Stay away fro' her," he growls. "She's not yer plaything."

"Gin," I murmur, sitting up. "Why are you helping me now when you tried to kill me back in Soul Society?"

"I never tried ta kill ya, Rin," he says.

"I recall your sword aimed right at my heart," I growl.

"Tha's because you jumped in fron' of it," he replies. I scowl and look away.

"Why did you leave in the first place?" I ask.

"Of course ya don' remember," he sighs. "Ya were too young." He's going back to our lives in the World of the Living, isn't he? Yes, we _were_ brother and sister in the World of the Living and _yes_ we remember our lives there, but we didn't stick together through the konso. I found him in Seireitei after I graduated the Academy. "Back in the World of the Living we were attacked by a Hollow. Aizen-taicho is the one who killed that Hollow an' performed konso on us. Aizen-taicho saved us."

A memory flickers through my mind. It's not as much of a memory as it is a feeling, but I can picture it. It's confusing. I remember a Hollow. And I remember a white haori. And a warm smile. Nothing about the person that smile belonged to, just how safe it made me feel.

But that smile… it's Aizen's. When he was still in Soul Society and pretended to be nice. It was _his_ smile.

I owe Aizen my life.

**A/N: Okay, I might have had that come a little early but hey *shrugs* what can you do? Anyways, the end of this is important, _especially_ the smile. Yes, I know that Aizen wasn't captain yet in the time period that Rin and Gin would have gotten the konso. So, her analyzing of her memories isn't exactly correct. That's a big point in this, so you'll just have to keep reading to find out! Oh, and I meant to say this sooner but the song _Always_ by Saliva is like the THEME SONG for this story. IT'S PERFECT!**


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